A feedback type exposure determining means is one means for determining exposure in a digital camera. That is, to always optimize the brightness of a liquid crystal screen of a digital camera, exposure is corrected by moving around at any instant, and image sensing exposure is determined by using data of the feedback type exposure determining means.
Also, a scan type exposure determining means performs photometry a plurality of times by using a plurality of predetermined exposure values, in order to compensate for abrupt brightness changes caused by scene changes. On the basis of this photometric data, optimum exposure is determined.
Unfortunately, the feedback type exposure determining means limits a time constant or correction value to some extent, in order to prevent oscillation of the exposure value. Therefore, this means cannot rapidly compensate for brightness changes caused by abrupt scene changes and hence cannot obtain correct exposure.
In addition, it is substantially impossible to effectively use the feedback system in an optical finder type digital camera having no liquid crystal screen or when a liquid crystal screen is turned off.
Also, the scan type exposure determining means must perform exposure a plurality of times. This produces a shutter release time lag.